| key_t | Alias for TKey  type | 
| msglen_t | Message length type | 
| msgqnum_t | Message queue number type | 
| PIPC_Perm | Pointer to TIPC_Perm  record. | 
| PMSG | Pointer to TMSG  record | 
| PMSGbuf | Pointer to TMsgBuf  record | 
| PMSQid_ds | Pointer to TMSQid_ds | 
| PSEMbuf | Pointer to TSembuf  record. | 
| PSEMid_ds | Pointer to TSEMid_ds  record. | 
| PSEMinfo | Pointer to TSEMinfo  record. | 
| PSEMun | Pointer to TSEMun  record | 
| PShmid_DS | Pointer to TSHMid_ds  record. | 
| PSHM_info |  | 
| TIPC_Perm | Record used in all IPC systems to specify the permissions. | 
| TKey | Type returned by the ftok  key generating function. | 
| TMSG | Record used in the handling of message queues. Do not use directly. | 
| TMSGbuf | Generic message data record | 
| TMSQid_ds | Record returned by the msgctl  call, contains all data about a message queue. | 
| TSEMbuf | Record used in semop  call. | 
| TSEMid_ds | Structure returned by the semctl  call, contains all data of a semaphore | 
| TSEMun | Record used in semctl  call. | 
| TShmid_ds | Record used in the shmctl  call to set or retrieve settings for shared memory. | 
| TSHMinfo | Record used by the shared memory system, Do not use directly. | 
| TSHM_info |  |